Nodally operated push-button switch

ABSTRACT

A snap-action operable push-button switch has a metal contact of rectangular shape having a pair of rectangular holes at both sides of a central stripe integrally formed therewith, the central stripe being bent toward one side thereof and the metal contact also having a pair of rectangular resilient contact pieces integrally extended therefrom in a size smaller than the size of the rectangular holes.

United States Patent Murata Aug. 12, 1975 [54] NODALLY OPERATEDPUSH-BUTTON 3,286,045 1 1/1966 Clark, Sr. et a1 200/5 R SWITCH 3,707,609l2/l972 Dapot et al. t t. 200/159 B 3,749,859 7/1973 Webb et al 200/5 R[75] Inventor; Taneo Murata, Tokyo, Japan 3,749,872 7/1973 Foster200/159 A [73] Assignee: Alps Electric Co., Ltd., Tokyo,

Japan Primary ExaminerDavid Smith, Jr. [22] Fued; Man 3 19 Attorney,Agent, or Firm-Guy W. Shoup Appl. No.: 450,865

Foreign Application Priority Data Mar. 16, 1973 Japan 48-30685 U.S. Cl.200/5 R; 200/5 A; 200/67 DB; 200/159 B Int. Cl HOlh 5/30; HOlh 13/64Field of Search 200/67 DB, 159 A, 159 B, 200/5 R, 5 A, 67 DA; 174/100 PReferences Cited UNITED STATES PATENTS 2/1917 Landis 200/67 DB [57]ABSTRACT A snap-action operable push-button switch has a metal contactof rectangular shape having a pair of rectangular holes at both sides ofa central stripe integrally formed therewith, the central stripe beingbent toward one side thereof and the metal contact also having a pair ofrectangular resilient contact pieces integrally extended therefrom in asize smaller than the size of the rectangular holes.

4 Claims, 14 Drawing Figures PAIENTEU AUG 1 2197s SPEET F/G.6A

NODALLY OPERATED PUSH-BUTTON SWITCH BACKGROUND OF THE INVENTION Thisinvention relates to a snap-action (nodally) operable push-button switchused for terminal equipment of electronic device.

It is an objective of the present invention to provide a snap-actionoperable push-button switch having improved electric characteristics;improved contacting sensitivity, and permitting rapid assembly for highproductivity of the siwtch.

It is another objective of the present invention to provide asnap-action operable push-button switch which makes point contact withstationary contacts on a printed circuit substrate and may alsopositively separate therefrom.

It is a further objective of the present invention to provide asnap-action operable push-button switch which may make contact softlyand may also provide sufficient play for knob (push-button) movement.

It is still another objective of the present invention to provide asnap-action operable push-button switch which may simplify theassembling process, reduce the number of wiring parts, and to simplifythe wiring process so as to economically assemble small electroniccomputers such as desk or hand electronic calculators.

It is still another objective of the present invention to provide anoperable push-button switch which is advantageous for producing thepush-buttons in relatively small numbers and with various types ofbuttons.

SUMMARY OF THE INVENTION According to the present invention, theoperable push-button switch, as one aspect, comprises a plurality ofoperating units mounted in a frame. Each unit has a sliding lever (not apivoting lever), a flexible conductive contacting plate with resilientcontact pieces, an insulating plate, a coil spring, and a case forenclosing the aforesaid parts to form a multi-key push-button assembly.The contacting plate includes a bent potion (a center strip) formed atthe center and bent reversely upon depression and also includingresilient contact pieces formed integrally with the bent portion therebyproviding a snap action or toggle like (nodal) operation.

These and other objects, features, and advantages of the push-buttonswitch according to the present invention will become more fullyapparent from the following description taken in conjunction with theaccompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. IA is a top plane view of theassembly of the snap-action push-button switch of the invention;

FIG. 1B is an enlarged sectional view of the switch taken along the lineIB-IB in FIG. 1A.

FIG. 2 is a perspective exploded view of the essential parts of theswitch of the invention;

FIG. 3A is a perspective view, partly broken away, of the back of theframe;

FIG. 3B is a perspective view of the back of the case of the switch,partly cut out;

FIG. 3C is a perspective view of the back of the lever, partly cut outof the switch;

FIG. 4 is a side sectional view of the operating unit of the switch ofthe present invention;

FIG. 5 is an enlarged side sectional view, in the engaged state, of theknob and the lever of the switch of the present invention;

FIGS. 6A and 6B are enlarged perspective views of the flexiblecontacting plate, in two steps of its manufacture;

FIGS. 7A to 7C are explanatory views of the operation of the flexiblecontacting plate which deforms at the central stripe thereof upondepression. Wherein FIG. 7A shows the state of the contacting platebefore it has been deformed, FIG. 7B shows the state of the contactingplate deforming upon the switch is closed, and FIG. 7C shows the stateof the contacting plate mostly deformed; and

FIG. 8 is a side sectional view of the essential part of anotherembodiment of the switch using a rubber resilient spring instead of thecoil spring of the prior embodiment.

Referring now to the drawings, numeral 1 indicates knobs (push-buttons),2 a frame and 3 an operating unit. The operating unit 3 includes a case4, a sliding lever 5, a coil spring 6, a flexible conductive contactingplate 7, and an insulating plate 8. Numeral 9 is a printed circuitsubstrate, and 10 are screws for mounting the printed circuit substrate9 to the frame 2.

The snap-action nodally operable push-button of the present inventioncomprises one frame 2, one printed circuit substrate, and plurality ofoperating units 3 (composed as above) and a plurality of knobs to form amulti-key push-button assembly.

The knobs (push-buttons) l are made of synthetic plastic resin, and, asshown in FIG. 5, have an integral cylindrical mounting shaft 11 engagedinto a hole 24 of the lever 5 at the lower center thereof. Each shaft 11has integral projections 12, 12 which oppositely project from both sidesof the end of the shaft 11 so that the knob l and the lever 5 are heldtogether. The root portion 13 of the shaft 11 is tapered.

As shown in FIG. 2, the frame 2 is made of synthetic plastic resin, andhas plural rectangular holes 14 aligned in a manner crossing at rightangles for slidably engaging the levers 5. The frame 2 also hascorresponding rectangular holes 15 (see FIG. 3A) formed stepwise to theholes 14 on the back of the frame 2 for engaging the rectangular cases4. Each of the cases 4 (see FIG. 4) includes a small-sized rectangularportion 18 and large-sized rectangular portion 19. The frame 2 has aplurality of thread holes 17 to receive the screws 10 for mounting theprinted circuit to the frame 2, at its peripheral edge and intermediateportion.

The cases 4 of the operating units 3 are made of synthetic plasticresin. Each case 4 has a small-sized hollow rectangular portion 18 andlarge-sized hollow rectangular portion 19 integrally formed therewith,and step 16 formed between the rectangular portions 18 and 19. As shownin FIG. 4, the lever 5 is slidably engaged with the inner wall of thesmall-sized hollow rectangular portion 18. The outer walls of thesmall-sized and large-sized hollow rectangular portions 18 and 19 areengaged with the holes 15 of the frame 2, respectively.

As shown in FIG. 38 a seat 20 is formed at the lower edge of thelarge-sized hollow rectangular portion 19 for mounting the movablecontacting plate 7 to the insulating plate 8. Projections 21 areprovided at the respective comers of the seat 20 for fixing the movablecontacting plate 7 and the insulating plate 8. Legs 22 are projected atthe opposite surfaces of the large-sized hollow rectangular portions 19for securing the case 4 to the printed circuit substrate 9, and claws 23are integrally projected from the end of the legs 22, respectivelyoutwardly. The legs 22 are resilient, and when the legs 22 are insertedinto the rectangular holes 36 formed at the printed circuit substrate 9under pres sure, the claws 23 of the legs 22 are engaged with the edgesof the rectangular holes 36 so that the cases 4 are secured to theprinted circuit substrate 9.

As shown in FIG. 3C, the sliding lever is made of synthetic plasticresin and has a hole 24 formed at its upper central portion thereof forengaging the shaft 11 of the knob 1 and the projections 12. Lever 5 hasa hole 25 for holding coil spring 6, the hole 25 being of a largerdiameter than the hole 24 at the lower portion thereof, and a step 26being formed between the hole 24 and 25. Stoppers 27 are formed at thelower portion of the lever 5 for preventing the lever 5, after havingbeen inserted into the case 4, from being discharged out. The stoppers27 are in contact with the step 16 of the case 4. The coil spring 6 isinserted into the hole 25 of the lever 5 in a manner that one endthereof is engaged with the step 26 and the other end thereof iscontacted with the center of the niovable contacting plate 7 to urge themovable contacting plate 7 and also to return the lever 5. The lever 5slides within an opening and is not a pivoting lever.

The flexible conductive contacting plate 7 is, for example, made ofphosphorus bronze thin metal plate having electroconductivity andresiliency. The plate 7 is punched, in the shape as shown in FIG. 6A, insuch a manner that a pair of rectangular holes are formed at both sidesof central stripe 28. The stripe 28 is integrally formed with the plateand a pair of rectangular resilient contact pieces are integrallyextended from the vicinity of the center of the stripe 28 in a size, anda shape, smaller than the size of the holes. Both side edges 29 of theplate 7 are parallel with the central stripe 28 and are drawn (or formedwith any alternative process) into a bump so as to shorten the sideedges compared to the central stripe 28 as shown in FIG. 6B. The centralstripe 28 is bent with the result that the resilient contact pieces 30extend from the central stripe 28. The contact pieces change directionrelative to the curve of the central stripe 28, Le. they are tangentialto the curve. The contact points 31, provided at the ends of theresilient contact pieces 30 are bent to the other side, (downwardly asseen in FIG. 6B). When the center of the bent portion of central stripe28 is depressed, the bent portion is reversely bent (see FIG. 7B) andwhen the depression is released, the bent portion returns to theoriginal bent state by the resiliency of the center stripe 28. There areprovided holes 32 at the respective four corners of the movablecontacting plate 7 for engaging (fitting upon) with the projections 21of the case 4.

The insulating plate 8 is made of synthetic plastic resin film, and issized to meet the size of the seat 20 of the case 4. There are providedholes 33 at the respective comers of the rectangular insulating plate 8for engaging with the projections 21 of the case 4. There are alsoformed rectangular holes 34 in the insulating plate 8 for inserting thefree ends of the resilient contact pieces 30, respectively. Therectangular holes 34 also enable the contact points 31 (at the ends ofthe resilient contact pieces 30) to make contact with the stationarycontacts 35 of the printed circuit substrate 9. The insulating plate 8insulates (other than its holes 34) the movable contacting plate 7 fromthe printed circuit substrate 9.

The desired circuit is formed on the printed circuit substrate 9. Theplural stationary contacts 35 are to be contacted with the contactpoints 31 of the resilient contact pieces 30. The printed circuitsubstrate 9 also has plural pairs of rectangular holes 36 formedtherethrough for inserting the legs 22, which mount the cases 4. Sincethe oblique surfaces of the claws 23 are contacted with the edges of therectangular holes 36, when the legs 22 of the cases 4 are inserted intothe rectangular holes 36 and the cases 4 strongly depressed, the legs 22are bent inside so that the ends of the claws 23 pass through therectangular holes 36. Simultaneously the bent portions of the legs 22are returned to their original states by their resiliency with theresult that the claws 23 are engaged with the edges of the rectangularholes 36 so that the cases 4 are secured to the printed circuitsubstrate 9. There are also provided plural holes 37 at the printedcircuit substrate 9 for inserting the screws 10. The mounting of theprinted circuit substrate 9 to the frame 2 may be made by alternativemeans instead of the screws 10.

Assemblying of the snap-action nodally operable push-button switch ofthe present invention will now be described.

The sliding lever 5 is inserted into the small-sized hollow rectangularportion 18 of the case 4, the coil spring 6 is then inserted into thehole 25 of the lever 5, the bent portion of the movable contacting plate7 is placed at the side of the coil spring 6 so that the holes 32 of thefour corners are engaged with the projections 21 of the four corners ofthe case 4, the movable contacting plate 7 is mounted to the case 4, theholes 33 of the four corners of the insulating plate 8 are engaged withthe projections 21 of the four corners of the case 4 in the state thatthe rectangular holes 34 of the insulating plate 8 coincide with thestationary contacts 35 of the printed circuit substrate 9, and theinsulating plate 8 is mounted to the case, then the projections 21 ofthe case 4 are punched, and then the movable contacting plate 7 and theinsulating plate 8 are fixed to the case 4, and thus the operating unit3 is assembled.

As shown in FIG. 4, the assembled operating unit 3 is so constructedthat the central stripe of the movable contacting plate 7 is bentupwardly as shown in the drawing, so as to push upwardly the coil spring6. The coil spring 6 urges upwardly the lever 5 with the result that thestoppers 27 of the lever 5 are contacted with the step 16 of the case 4so as to prevent the lever 5 from being discharged out. The desirednumber of the operating units 3 are previously assembled, and then thelegs 22 of the case 4 of the operating unit 3 are press-fitted within apair of rectangular holes 35 of the printed circuit substrate 9, andthen the claws 23 of the legs 22 are engaged with the edges of the pairof rectangular holes 36 so that the operating units 3 are secured to theprinted circuit substrate. Thus, a desired number of operating units 3are mounted to the printed circuit substrate 9.

Then, the cases 4 of the respective operating units 3 are engaged withthe holes l5 of the frame 2, i.e., the frame 2 is located on pluraloperating units 3, and then screws 10 are inserted into plural holes 37of the printed circuit substrate and are screwed with the thread holes17 of the frame 2 and are then tightened so as to secure the printedcircuit substrate 9 to the frame 2, and the operating units 3 are fixedbetween the printed circuit substrate 9 and the frame 2. Then, themounting shafts 11 of the respective knobs 1 are engaged so as topress-fit the projections 12 to the holes 24 of the levers 5 presentedat the holes 14 of the frame 2 thereon, and then the knobs 1 are turnedat 90 so as not to be discharged out from the lever 5 to complete theassembling.

Then, the operation of the nodally operable pushbutton switch of thepresent invention will now be described.

The central stripe 28 of the movable contacting plate 7 of thepush-button switch, assembled but not yet operated, is bent upwardly asin FIG. 7A. At the side of the lever 5, the free ends of the resilientcontact pieces 30 are also directed upwardly. The contact points 31 (atthe free ends of the resilient contact pieces 30) are separated from thestationary contacts 35 of the printed circuit substrate 9, and thepush-button switch is in its open state. The bent portion of the centralstripe 28 of the movable contacting plate 7 pushes the lever S and theknobs 1 upwardly, and the stoppers 27 of the lever S are contacted withthe step 16 of the case 4 to hold the lever S in the stopped state.

When the knob 1 is now depressed, the lever 5 compresses the coil spring6, which spring 6 urges the center of the central stripe 28 of themovable contacting plate 7. When the coil spring 6 is compressed to acertain degree, the central stripe 28 is also started to be in flexure,and when the coil spring 6 is further compressed, the central stripe 28cannot endure the depression so that the central stripe 28 is abruptlydeformed from the state shown in FIG. 7A to that shown in FIG. 713, withthe result that the center of the central stripe 28 is reversely bentand the inclined direction of the resilient contact pieces 30 are alsoabruptly changed so that the contact points 31 are abruptly moveddownwardly. The contact points 31 are then positively contacted with thestationary contacts 35 of the printed circuit substrate 9, and then thecircuit is closed. The reversing speed of the central stripe 28 of themovable contacting plate 7 when reversely bent is faster than the movingspeed of the knob 1 up to that time, (a type of toggle action), and thedepression to the knob 1 when reversely bent is abruptly reduced, andaccordingly the knob l is nodally moved. When the knob l is furtherdepressed even after the circuit is closed, the coil spring 6 and thecentral stripe 28 of the movable contacting plate 7 are furthercompressed so that the central stripe 28 of the movable contacting plate7 becomes as shown in FIG. 7C so as to provide sufficient movingallowance of the knob 1. When the depression is released, the centralstripe 28 of the movable contacting plate 7 urges the coil spring 6, byits own resiliency, and returns to its original bent state and the coilspring 6 is also returned to its original state by its resiliencythereof so as to simultaneously return the knob 1.

A resilient member such as spring 38, see FIG. 8, formed of rubber ofrubber resilient material as shown in FIG. 8 may be used instead of thecoil spring 6.

The following advantages and effects can be provided by the nodallyoperable push-button switch of the invention:

It should be understood from the foregoing description that since thenodally operable push-button switch of the present invention comprisesthe movable contacting plate 7 which is shortened at the edges 29 bydrawing so that the opening and closing of the switch is nodallyconducted and the switch also comprises spherical contact points 31 atthe free end of the resilient contact pieces 30 so as to effectpoint-contact with the stationary contacts 35 on the printed circuitsubstrate 9, positive separation of the point contacts 35 can beattained so as to improve the electric characteristics.

It should also be understood that since the coil spring 6, such asresilient material made of rubber or rubber substance, is disposedbetween the movable contacting plate 7 and the lever 5 in the switch ofthe invention, the contacting sensitivity of the contacts is soft andthe play of the moving degree of the knob 1 may be sufficiently providedso as to improve the contacting sensitivity.

It should also be understood that since the nodally operable push-buttonswitch of the invention comprises wiring portion of operational circuit,stationary contacts and circuit portion of push-button switch formed onone printed circuit substrate and said operational circuit mounted atthe wiring portion of the operational circuit, operating units mountedat the pushbutton switch portion as one-touch operation type sim plyassembled compared with the conventional desk type electronic computerwhich as separate pushbutton portion and operational circuit portion andlead wires for connection the former to the latter, the assemblingprocess, wiring parts and the number of wiring processes can be reducedso as to assemble the desk type electronic computer less expensively.

It should also be understood that since the knobs 1 and frame 2 andoperation units 3 are combined with the printed circuit substrate 9 inthe switch of the present invention, so that when push-button switchesfor different key numbers are produced, only the designs of printedcircuit substrate and the frame 2 may be changed and when differentdesign of the knob l is necessary, only the knob l of different designmay be formed and may be mounted thereto, it is advantageous forproducing small numbers and various types of pushbutton switches.

What is claimed is:

l. A nodally operable push-button switch comprising a case, and aflexible conducting metal plate, said plate having a normally curvedcentral stripe and a pair of rectangular holes at both sides of saidcentral stripe integrally formed therewith and also having a pair ofresilient contact pieces integrally extended therefrom smaller than thesize of the holes, and opposite side edges of said metal plate beingdrawn so that they are shorter than the said central stripe.

2. A nodally operable push-button switch as set forth in claim 1,further comprising a lever mounted slidably into said case, and aresilient means disposed between the said curved central stripe and saidlever.

3. A nodally operable push-button switch as set forth in claim 2,further comprising a printed circuit substrate having stationarycontacts, and a frame. said case having legs with claws integrallyprojected therefrom said claws being engaged with holes provided in saidprinted circuit substrate, said lever being slidably inserted into saidcase, and an insulating plate provided on said printed circuit substrateand having a pair of rectangular holes formed therethrough forcontacting said stationary contacts.

4. A nodally operable push-button switch as set forth in claim 1,further comprising a printed circuit substrate having a plurality ofstationary contacts, a frame having a plurality of holes aligned in amanner crossing at right angles with each other, a plurality of caseseach having legs, each of said legs having claw portion for engagingwith said printed circuit substrate, a lever slidably inserted into saidcase, a movable contacting plate disposed at the bottom of said case,said contacting plate having a central strip with a bent portion andhaving a pair of rectangular holes at both sides of central stripeintegrally formed therewith and also having a pair of rectangularresilient contact pieces integrally extended therefrom which are smallerthan the size of the holes, and opposite side edges of said metal platebeing drawn to be shorter than the central stripe of said metal plate,an insulating plate having a pair of rectangular holes for contactingthe stationary contacts provided on said printed circuit substrate, saidlever having a spring hole, a resilient material inserted between thespring holes of said lever and the bent portion of said movablecontacting plate to form an operating unit, a plurality of saidoperating units mounted to said printed circuit substrate and saidframe, and a plurality of knobs with mounting shafts engaged with theholes of said levers, said levers being slidably inserted into the holesof said frame.

1. A nodally operable push-button switch comprising a case, and aflexible conducting metal plate, said plate having a normally curvedcentral stripe and a pair of rectangular holes at both sides of saidcentral stripe integrally formed therewith and also having a pair ofresilient contact pieces integrally extended therefrom smaller than thesize of the holes, and opposite side edges of said metal plate beingdrawn so that they are shorter than the said central stripe.
 2. Anodally operable push-button switch as set forth in claim 1, furthercomprising a lever mounted slidably into said case, and a resilientmeans disposed between the said curved central stripe and said lever. 3.A nodally operable push-button switch as set forth in claim 2, furthercomprising a printed circuit substrate having stationary contacts, and aframe, said case having legs with claws integrally projected therefromsaid claws being engaged with holes provided in said printed circuitsubstrate, said lever being slidably inserted into said case, and aninsulating plate provided on said printed circuit substrate and having apair of rectangular holes formed therethrough for contacting saidstationary contacts.
 4. A nodally operable push-button switch as setforth in claim 1, further comprising a printed circuit substrate havinga plurality of stationary contacts, a frame having a plurality of holesaligned in a manner crossing at right angles with each other, aplurality of cases each having legs, each of said legs having clawportion for engaging with said printed circuit substrate, a leverslidably inserted into said case, a movable contacting plate disposed atthe bottom of said case, said contacting plate having a central stripwith a bent portion and having a pair of rectangular holes at both sidesof central stripe integrally formed therewith and also having a pair ofrectangular resilient contact pieces integrally extended therefrom whichare smaller than the size of the holes, and opposite side edges of saidmetal plate being drawn to be shorter than the central stripe of saidmetal plate, an insulating plate having a pair of rectangular holes forcontacting the stationary contacts provided on said printed circuitsubstrate, said lever having a spring hole, a resilient materialinserted between the spring holes of said lever and the bent portion ofsaid movable contacting plate to form an operating unit, a plurality ofsaid operating units mounted to said printed circuit substrate and saidframe, and a plurality of knobs with mounting shafts engaged with theholes of said levers, said levers being slidably inserted into the holesof said frame.